I carry a buck 110 on my belt, and a small victorinox tinker in my watch pocket. They compliment each other well. The scissors get the most use. They are great for trimming flies, and those plastic tag things when you buy a shirt. Nice to have the tooth pick and tweezers, and the little blade does things the buck cannot. It also comes in handy when somebody else asks to borrow a knife, and I don't want to give them my buck. @ $13 to $19 it is almost disposable.
I keep a lot of 4 way screw drivers around, so I don't really need silly screw drivers on my knife.
For reference, I spent my youth with a 4 blade victorinox in my pocket, I would open every can and, bottle cap, I could find, but found the screw driver less than satisfactory. It digs into your hand after just a few turns on a screw. I think I only got to use the corkscrew once.
Then carried a champion for a few years, that was fun, but it was too bulky when you just needed the blade. Although the magnifying glass worked very well with the tweezers, and had at least the potential to help light a fire.
If you really need a bulky knife with lots of tools that actually work, the leatherman is a much better choice.
So any victorinox that fits in your pocket is useful, the explorer looks like a good choice, it is the smallest knife that has the magnifying glass. For belt duty, go with a leatherman wave, or similar.